1. Field of the Invention
The present invention relates to a perpendicular magnetic write head that executes a recording process of a perpendicular magnetic recording method, a method of manufacturing the same, and a magnetic recording apparatus on which the perpendicular magnetic write head is mounted.
2. Description of the Related Art
In recent years, as the surface recording density in a magnetic recording medium (hereinbelow, called “recording medium) such as a hard disk increases, improvement in the performance of a thin film magnetic head mounted on a magnetic recording apparatus such as a hard disk drive is in demand. Known recording methods of a thin film magnetic head include the longitudinal recording method of setting the direction of signal magnetic fields to an in-plane direction (longitudinal direction) of a recording medium and the perpendicular recording method of setting the direction of signal magnetic fields to a direction crossing the plane of the recording medium. At present, the longitudinal recording method is widely used. However, considering the market trend accompanying the improvement in surface recording density, it is assumed that the perpendicular recording method will be regarded as a more promising method in place of the longitudinal recording method in future. The perpendicular recording method has advantages such that linear recording density is higher and a recorded recording medium is not susceptible to the influence of thermal fluctuations.
A thin film magnetic head of the perpendicular recording method (hereinbelow, called “perpendicular magnetic write head”) has a magnetic pole for generating a magnetic field for writing (so-called perpendicular magnetic field). With the perpendicular magnetic write head, a recording medium is magnetized by the magnetic field for writing, so that information is magnetically recorded on the recording medium.
A perpendicular magnetic write head having a magnetic pole which extends in the direction crossing the air bearing surface is known (refer to, for example, Japanese Unexamined Patent Application Publication Nos. H02-066710 and 2002-197615). The perpendicular magnetic write head of this kind is generally called a “single-magnetic-pole-type head”. It is however said that the single-magnetic-pole-type head has limitation in improvement of recording density of a recording medium.
A perpendicular magnetic write head which is recently the mainstream has a shield for capturing a magnetic flux around the magnetic pole in order to suppress spread of the magnetic field for writing and prevent information recorded on a recording medium from being unintentionally erased. The perpendicular magnetic write head of this kind is generally called a “shield-type head”. There are three kinds of shields: two side shields disposed on both sides of the magnetic pole in the write track width direction; a leading shield disposed on the leading side of the magnetic pole; and a trailing shield disposed on the trailing side of the magnetic pole. Known concrete structures of the perpendicular magnetic write head having the shields include a structure having only side shields (refer to, for example, Japanese Unexamined Patent Application Publication No. 2004-127480), a structure having only the trailing shield (refer to, for example, Japanese Unexamined Patent Application Publication No. 2001-250204 and European Patent Application Publication No. 0,360,978), a structure having the side shields and the leading shield (refer to, for example, U.S. Pat. No. 4,656,546), a structure having the side shields and the trailing shield (refer to, for example, Japanese Unexamined Patent Application Publication No. 2005-190518), and a structure having the side shields, the leading shield, and the trailing shield (refer to, for example, U.S. Pat. Nos. 6,954,340 and 7,042,682).
In the recent perpendicular magnetic write head manufacturing field, as a film forming method having extremely excellent film thickness controllability, ALD (Atomic Layer Deposition) is used (refer to, for example, “ALD atomic layer deposition apparatus”, Techscience Ltd, (URL: http://techsc.co.jp/products/mems/ALD.htm)). The ALD is a method capable of forming an oxide film, a nitride film, a metal film or the like extremely thinly and densely under a high temperature condition of 150° C. or higher. The ALD is widely used in the manufacturing method strictly requested to have a physical parameter such as a withstand voltage. In the manufacture field of the perpendicular magnetic write head, the ALD is used in a step of forming a reproduction gap (refer to, for example, U.S. Pat. No. 6,759,081).